This invention relates to an identification system comprising an interrogator and a plurality of transponders.
South African Patent application No. 92/0039 describes an identification system which comprises an interrogator and a number of individual transponders, each transponder being associated with an article to be identified. The articles to be identified may be vehicles, items of stock in a supermarket or warehouse, or humans, for example.
In the system described in the abovementioned patent application, it is possible under extreme circumstances that the signal from one transponder which is relatively far away from the interrogator could be swamped by the signal from a nearby transponder, leading to non-identification of the transponder which is further away.
It is an object of the invention to improve the reliability of transponder identification in a system of the kind referred to above.